The current flowing through the 5 \( \Omega \) resistor is given as 0.5 A. Using Ohm's law, \( V = IR \), we can find the voltage across the 5 \( \Omega \) resistor.
\[
V = I \times R = 0.5 \, \text{A} \times 5 \, \Omega = 2.5 \, \text{V}
\]
Now, considering the series and parallel combinations of resistors, we can calculate the total voltage \( E \) applied to the circuit by adding the appropriate voltage contributions across the resistors. After doing the necessary calculations for each resistor in the network, we find the value of \( E \) to be 6 V.
Thus, the correct answer is option (2), 6 V.